The HsIndex Service

  The HsIndex service is an event driven service that is set to wait for a user configurable star graph. The most frequently used star graph for HsIndex is a bale.HaystackDocument attached to a needle.Text. When the HsIndex service is notified of the existence of such a sub-graph it will ad a pointer to the subgraph in a queue. Periodically it will test to see if the cluster is in stable state. Once the bale.HaystackDocument has arrived in stable state, the HsIndex service invokes the getIndexable() method. The result of this call is some text.

HsIndex will check to see which IR systems the Haystack is configured to use, and will pass the text to that IR system for indexing. Currently the only defined IR system interface in Haystack is to the Isearch system [16], which is defined in haystack.service.ir.HsIsearch. HsIsearch extends the class haystack.service.ir.IRSystemService which has a large set of utility functions for taking the text generated by HsIndex and generating something that IR systems can index.